Apostrophe Use: Contractions and Omissions
Contractions and omissions have been an integral part of daily writing, thanks to the apostrophe. Contractions are formed when a letter or sound is omitted from a word to make for easier and faster flow.
Popular contractions are usually made up of auxiliaries, verbs or modals that are attached to other words. Examples are I had = I'd, they have = they 've, he cannot = he can't, etc.
In informal writing, you will likely not go wrong using a contraction. However, since contractions denote a less serious tone, avoiding them in formal writing is preferred. There are of course unavoidable cases like o'clock where using "of the clock" is rare. But other than such rare cases, you'll want to only use contractions in casual writing.
Apostrophes and Possessive Nouns
Confusion is most often encountered when forming possessives. The following rules apply when changing nouns to possessives.
Singular nouns are changed to possessive nouns by adding an apostrophe and "s," e.g., The computer's hardware, The scientist's kit, etc.
Only an apostrophe is added to most plural nouns. i.e., The computers' hardware, The scientists' kit, etc.
An apostrophe + s is added to plural nouns that have no "s" in the ending. Thus; The oxen's ranch, The equipment's store, etc.
There are differences in style guides when changing singular proper nouns with an "s" ending to possessive nouns. While some believe they should only go with an apostrophe, as in; Phillips' trademark, others stick with both apostrophe and "s," i.e., Phillips's trademark.
However, regardless of your chosen style guide, it's always best practice to turn plural proper nouns to possessives by adding only the apostrophe. E.g. The Johnsons' family.
Apostrophes and Possessive Pronouns
In contrast to regular nouns, apostrophes are not added to personal pronouns when changing them to possessives. In most cases mine, my, her, his and our are easy to use. Some concerns for some writers is in using yours, your, ours, its, hers, theirs, etc.
How to Write Joint Possession
How about using the apostrophe when talking about something that is not possessed by a single person? If there are multiple owners of something, the golden rule is to use the apostrophe only on the final name. E.g. Mike and Grace's team won the tournament.
Apostrophes and Plurals
A common mistake is to use apostrophes where there is no need for one, in a fruitless bid to change such nouns to plurals. For example, saying "10 apple's for $2". Except in very few occasions like "Remember to cross your t's," there's nowhere using an apostrophe will change nouns to plurals.
When to Check a Style Guide
There are going to be cases where words will sound perfectly fine when spoke but appear puzzling on paper. When you experience such scenarios, and you'll likely experience one as a writer, the best thing to do is look up the word on a comprehensive style guide or a trusty dictionary, and you should be fine.